(1) Introduction to phosgene and phosgene process.
Phosgene, also known as carbonyl chloride, with the chemical formula CoCl2, is an important organic intermediate and a very active electrophile. It is highly toxic, non-flammable, has high chemical reactivity, and is strongly corrosive when exposed to water. Slightly soluble in water, soluble in most organic solvents such as aromatic hydrocarbons, benzene, carbon tetrachloride, chloroform, acetic acid, etc. It is made from a mixture of carbon monoxide and chlorine by activated carbon. Phosgene is a colorless gas at room temperature, with a smell of rotting grass, a yellow-green liquid at low temperature, unstable chemical properties, and rapid hydrolysis in case of water, generating one of the high-temperature pyrolysis products of chlorine plastics. used as an intermediate in organic synthesis, pesticides, drugs, dyes and other chemical products. Aliphatic chlorocarbons (such as chloroform, trichloroethylene, etc.) can produce phosgene when burned. Phosgene in the environment mainly comes from production processes such as dyes, pesticides, and pharmaceuticals. Inhalation of phosgene can damage the respiratory tract, leading to chemical bronchitis, pneumonia, pulmonary edema. When inhaled at higher concentrations of phosgene, it can cause severe poisoning and even death. Carbonyl chloride
The first lesson of enterprise safety production phosgene and phosgene process includes the preparation process of phosgene, and the process of preparing phosgene products with phosgene as raw material, and the phosgene process is mainly divided into gas phase and liquid phase. There are mainly the following typical chemical reactions in the process of phosgene and phosgene products:
1.Carbon monoxide reacts with chlorine to synthesize phosgene.
2.Phosgene synthesizes double phosgene.
3.Phosgene synthesizes three phosgene.
4.Phosgene is used as a monomer to synthesize polycarbonate.
5.Toluene diisocyanate (TDI) preparation.
6.Preparation of 4,4-diphenylmethane diisocyanate (MDI).
2) Hazardous characteristics of phosgene and phosgene process.
The phosgene and phosgene process is divided into phosgene synthesis process and the process of using phosgene as raw material to synthesize phosgene products. The main process hazard characteristics are:
1.Phosgene is a highly toxic gas, which is easy to cause large-scale pollution and poisoning accidents after leakage occurs during storage, transportation and use.
2.The reaction medium is a risk of ignition and explosion.
3.The by-products are corrosive, easy to cause equipment and pipeline leakage, and cause personnel to be poisoned.
3) Focus on monitoring process parameters of phosgene and phosgene.
In the process of phosgene and phosgene chemical process, due to the explosiveness and toxicity of the reaction medium, there are many units involved in the danger, and there are many process parameters to be monitored, among which the most important process parameters are as follows
1.Carbon monoxide, chlorine water content.
2.Reactor temperature, pressure.
3.The ingredient ratio of the reactive substance.
4.phosgene feed rate.
5.The temperature, pressure, and flow rate of the cooling medium in the cooling system.
The phosgene and phosgene processes have a certain impact on operators, the environment and production equipment, and strict safety measures and operating procedures need to be taken to ensure production safety. At the same time, it is also extremely important to carry out phosgene process training to improve the safety awareness and safety prevention ability of employees.